Technical data

Autorefresh not refreshing cache at the specified interval
4-16 Oracle TimesTen In-Memory Database Troubleshooting Procedures Guide
enabled, the parallel query optimizer generates a query plan that allows the
original query to be broken into sections to be worked concurrently by different
parallel query slave processes. When using parallel query, users should assign a
default degree of parallelism of (2*N) to the cache group base table, where "N" is
the number of CPUs on the machine. Then, experiment to understand what level
of parallelism works best for their environment. Experiment with different table
structures for base tables, as follows:
– Use a standard heap table with default degree of parallelism assigned during
table creation or by use of the ALTER TABLE PARALLEL command. Build an
N-partition primary key index against the table.
– Use an N-way partitioned table structure with partition range key based either
on the table primary key or, in the case of a concatenated primary key, the
high-order column of the primary key. The number of partitions should be set
to the degree of parallelism. Use a local primary key index with the same
number of partitions.
– Use an N-way hashed partition structure using the primary key as the hash
key, a local paritioned primary key index, and both index and table partitions
equal to the degree of parallelism. The log table should not be partitioned, as
the cardinalities of the log table should never be large enough that a
paritioned log table would have any performance benefit. Further, given the
continuously increasing value of the log table primary key column, range
partitions cannot be used.
Autorefresh not refreshing cache at the specified interval
The following table shows possible causes for autorefresh problems.
Possible cause What to do
Cache agent not started with a cache
administration user
Specify a cache administration user ID and
password when starting the cache agent, as
described in "Starting the cache agent" in the
Oracle In-Memory Database Cache User's Guide.
Object ID of the base table has changed. See "Recover and reset autorefresh Oracle objects"
on page 4-17.
Autorefresh trigger not enabled See "Recover and reset autorefresh Oracle objects"
on page 4-17.
Current log sequence number recorded in
the TT_version_USER_COUNT table is
less than to the maximum log sequence
number in the autorefresh log table.
See "Recover and reset autorefresh Oracle objects"
on page 4-17.
There is no row in the TT_version_
USER_COUNT table with usercount > 0
for every active incrementally autorefresh
table
See "Recover and reset autorefresh Oracle objects"
on page 4-17.
Change log table is empty. See "Recover and reset autorefresh Oracle objects"
on page 4-17.
User count is less than 0 or any TT_
version_USER_COUNT log sequence
anomalies
See "Recover and reset autorefresh Oracle objects"
on page 4-17.